(19)
(11) EP 0 423 763 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
11.09.1991 Bulletin 1991/37

(43) Date of publication A2:
24.04.1991 Bulletin 1991/17

(21) Application number: 90119923.2

(22) Date of filing: 17.10.1990
(51) International Patent Classification (IPC)5G01N 23/223, G01V 5/00
(84) Designated Contracting States:
CH DE FR GB IT LI

(30) Priority: 19.10.1989 US 423831

(71) Applicant: Hughes Aircraft Company
Los Angeles, California 90045-0066 (US)

(72) Inventors:
  • Webster, Jackie R.
    Irvine, CA 92714 (US)
  • Pearson, Keith V.
    Long Beach, California 90807 (US)
  • Chang, David B.
    Tustin, CA 92680 (US)
  • Moise, Norton L.
    Pacific Palisades, CA 90272 (US)
  • Vali, Victor
    Laguna Hills, CA 92653 (US)

(74) Representative: Grünecker, Kinkeldey, Stockmair & Schwanhäusser Anwaltssozietät 
Maximilianstrasse 58
80538 München
80538 München (DE)


(56) References cited: : 
   
     
    Remarks:
    A request for numbering and position of claims 6 and 7 has been filed pursuant to Rule 88 EPC. A decision on the request will be taken during the proceedings before the Examining Division (Guidelines for Examination in the EPO, A-V, 2.2).
     


    (54) X-ray fluorescence imaging of elements


    (57) A system for detecting the presence of known materials in a body or contain­er. The system incorporates a gamma or X-ray source for irradiating the body with gamma rays to produce X-ray fluorescence of materials contained therein. A direc­tionally discriminate X-ray detector is positioned to intercept X-rays emitted from the body and is adapted to pass only those X-rays having a predetermined wavelength and incident from a specific direction that are characteristic of a material of interest contained in the body. The detector includes a dislocation free single crystal having substantially parallel input and output surfaces. A second crystal aligned parallel to the first crystal may be disposed at a position offset from the first crystal to receive the X-rays transmitted by the first crystal in order to discriminate between materials fluorescing within the body. In a specific embodiment of the invention, the first de­tector comprises an elongated crystal which pass X-rays in accordance with the Bor­rmann effect. A plurality of the crystals are arranged in a linear array and the con­tainer is either scanned with the array or the container passed linearly past the array. The detected X-rays are measured in intensity and the data is processed by suitable data processor to generate a video image indicative of the presence and shape of the specific materials for which the system is adapted. In yet another specific embodi­ment of the invention, a plurality of such arrays can be arranged with the input sur­faces of the crystals disposed at different Bragg angles to simultaneously detect the presence of a selected group of materials.







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